This invention relates generally to microwave spectroscopy, and particularly relates to a method of and apparatus for identifying the nature of cells such as malignant cells.
Some time ago it was discovered that the microwave absorption of normal and tumorous or malignant cells differs. This has been pointed out by a paper by Webb and Booth entitled "Microwave Absorption by Normal and Tumor Cells" which appears in Science, Vol. 174, October 1, 1971, pages 72-74. In this paper, the microwave absorption of cells or tissues has been measured at various discrete frequencies by a Klystron. The frequency range from 66 to 76 GHz was used. Each set of cells was measured separately and the results were subtracted from each other.
Due to the fact that separate measurements had to be made at different frequencies, it is difficult to compare the measurements with each other. It is equally difficult or laborious to subtract the attenuation obtained from one set of cells from that of another. Therefore, the so called base line could not be established with any degree of certainty. That is, it is not certain whether results obtained at one frequency are comparable to those obtained at another frequency. For these reasons, the method disclosed in the Webb et al. paper could not be used for identifying a particular type of cell or distinguishing it from normal cells.
It is frequently desired to determine the nature of tissues taken from a patient during an operation. In this case, a long waiting period can often not be tolerated because the surgeon cannot wait an indefinite period of time until finishing the operation. Even with modern methods it may take an appreciable time to obtain an analysis whether the tissue is cancerous or not with any degree of certainty.
In some cases the specimen taken from a patient may have to be prepared for subsequent culture using sterile procedures. In this case, the tissue may have to be grown and passed through several passages before it can be analyzed. As a result, it is possible that the tissue materially changes its nature before it can be analyzed. For example, if the original tissue showed a certain degree of malignancy, the tissue, after several passages, may show nothing but malignant cells, or it may even show nothing but normal cells. Thus, the serially passed culture may have cells which change their morphologic appearance and, therefore, an absolute identification may not be possible.
It is accordingly an object of the present invention to provide a method of and apparatus for identifying the nature of cells which can be effected rapidly and without the need to grow cells over various passages.
A further object of the present invention is to provide a microwave analysis of cells which can be rapidly carried out and which positively identifies various types of malignancy, such as, for example, carcinoma, sarcoma and melanoma.
Still another object of the present invention is to provide a system of the type discussed which will permit the simultaneous comparison of normal cells with malignant cells, both being autologous cells.